Scintillation camera and multifocal fan-beam collimator used therein

Abstract

A fan-beam collimator has a plurality of focal lengths. The shortest focal length is located at the center of the collimator. The longest focal length is located at the periphery of the collimator. The focal length increases between the minimum focal length and the maximum focal length.

What is claimed is: 
     
       1. A scintillation camera system, comprising a scintillation camera head and fan-beam collimator having a plurality of focal lengths. 
     
     
       2. A scintilation camera system, comprising a scintillation camera head and a fan-beam collimator which focuses to a plurality of coplanar focal points. 
     
     
       3. The scintillation camera system of claim 2, wherein the focal points are all coplanar with a centerline of the collimator. 
     
     
       4. A fan-beam collimator having a plurality of focal lengths, the focal length of the collimator being at a minimum value adjacent a centerline of the collimator, the focal length of the collimator being at a maximum value adjacent two opposed peripheral regions thereof and the focal length of the collimator nondecreasing from said minimum value to said maximum value as distance from said centerline increases. 
     
     
       5. The collimator of claim 4, wherein the focal length of the collimator varies in discrete steps. 
     
     
       6. The collimator of claim 4, wherein said minimum value is approximately 45 cm and said maximum value is approximately 130 cm. 
     
     
       7. The collimator of claim 4, wherein the focal length of the collimator varies in such small discrete steps as to simulate continuous variation.